This is what conflicts in my mind.
Trayvon, as is not disputed, was trying to avoid Zimmerman - at one point running or nearly running to avoid this person who was stalking him in his truck. He was obviously scared as crap as most 17 year olds are at night when they feel they are being followed.
Then, Zimmerman claims he came upon Trayvon on foot (ignoring pleas not to, obviously convinced he was catching a criminal in the act) engaged him in conversation, and that Trayvon launched and punched him square in the mouth when Zimmerman was reaching in his pocket to call the police again. Then while on top of him, Trayvon pinched his nose and covered his mouth to try and suffocate him. During the strugge Zimmerman's jacket came up revealing the handgun, Trayvon saw it, paused, and said "You're dead now motherroughrider" and started reaching for it but not before Zims could pull it out and shoot him.
Now, how Trayvon went from someone who was trying to avoid a situation into wanting to kill someone and then at the very same time Zimmerman (who had been stalking him) transformed from an armed aggressor into a total pacifist acting in self-defense is a fact I can't reconcile in my mind.